Telephone system



July 21, 1936. P. HUSTA TELEPHONE SYSTEM Filed March 7, 1935 2SheetsSheet l INVENTOR By RHUSTA $15M ATTORNEK July 21, 1936. P. HUSTATELEPHONE SYSTEM Filed March '7, 1935 2 Sheets-Sheet 2 NON INVENTOR P.HUS T4 ATTORNEY Patented July 21, 1936 rnnnrnonn srs-rnm Philip Hum.Great NeckQN. r., asslgnor to Bell Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application Mal-ch 1, 1935,Serial No. 9,693

4 Claims.

This invention relates to signaling systems and more particularly tosystems in which recording devices are operated in response to impulses.

5 The invention is particularly adaptable to dial telephone systems inwhich series of impulses dialed by a subscriber or operator are recordedin a central oflice sender for the purpose of setting digit registers tocontrol the selective operation of selector switches. In order thatproper response to dialed impulses may be obtained over both long andshort dialing loops, it is essential that the responsive apparatus shallbe accurately and sensitively responsive to the impulses.

It is therefore the object of the invention to provide an impulseresponsive device whereby more accurate and faster impulse response maybe realized over long dialing loops.

In accordance with the present invention, this object is realized byutilizing gaseous conductor or discharge tubes to respond to dial orother sources of impulses which in turn control relays.

a record of the series of impulses dialed or transmitted. The gaseousconductor tubes employed are of the type filled with a low pressuregaseous content which, for purposes of illustration, might be neon,argon, helium, mercury vapor or combinations of gases of this group. Atube of this character has a certain characteristic, namely, that thegaseous content will become ionized and thus conducting on one potentialdetermined by the electrode design, the nature of the gaseous contentand its pressure, but once rendered conducting will maintain thiscondition of conductivity on a much lower potential. The tubes may be ofthe hot cathode type having their cathodes heated by conduction fromfilaments energizedby direct current as illustrated or the filaments maybe energized by alternating current or the filaments may be heated bydirect current and themselves serve as cathodes. The tubes might also beof the cold cathode type.

The invention has been illustrated in two modifications both of whichshow a dialing loop extending from a subscribers substation to animpulse recording device, the recording device in- 50 eluding tengaseous discharge tubes which are successively responsive to a maximumof ten impulses in any dialed impulse series. rA transformer isinterpolated between the dialing loop and the recording device with itswindings so 55 poled with respect to each other that only the The relaysmay control registers to make surges of potential inducedv in thesecondary winding thereof upon the openings of the dialing loop by thesubstation dial are efiective to cause the breakdown or ionization ofthe tubes. Each tube has an anode relay connected in the 5 cathode-anodecircuit thereof which becomes 0perative when the tube with which it isassociated ionizes. Each anode relay, in addition to other functions tobe-later described, is instrumental in assisting in the control of aregistering de-' 10 vice.

In accordance with one embodiment of the invention, the controlelectrode of only the first of the ten tubes is normally associated withthe secondary winding of the transformer, anode po- 15 tential beingsupplied to all of the tubes upon the initial-closure of the dialingloop. The control electrodes of the remaining tubes are normallydisassociated from the secondary winding of the transformer. tube,except the last, is provided with contacts which, upon the operation ofthe relay, connect the control electrode of the next succeeding tube tothe secondary winding of the transformer.

The circuit functions in the following manner: 25 Upon the initialclosure of the dialing loop, anode potential is connected to the anodesof all ten tubes through the windings of the associated anode relays andan inductive surge of potential is generated in the secondary winding30.

' of the transformer which increases the negative bias on the controlelectrode of, the first tube. In response to the first dialed impulse,the dialing loop is momentarily opened, thereby causing a surge ofpotential of the opposite ,po- 35 larity in the secondary winding of thetransformer which reduces the bias on the control electrode of the'firsttube to such a degree that the first tube ionizes and operates its anoderelay over its cathode-anode circuit. This anode 40 relay closes aregister operating circuit and con-v nects the control electrode of thesecond or next succeeding tube to the secondary winding of thetransformer. On the next closure of the dialing loop the negativebias-on the control electrode of the first two tubes is increased butwithout effect on either tube, the'first tube remaining in its ionizedcondition and the second tube being blocked against ionization. 0n thenext opening of the dialing loop the resulting surge of potential in thesecondary winding of the transformer reduces the bias on the controlelectrode of the second tube to such a degree that the second tubeionizes and operates its anode relay. This anode relay closes a registeroper- The anode relay of each 29 ondary winding of the transformer. In asimilar manner in response to successive closures and openings of thedialing loop successive tubes ionize and operate their anode relays. thenumber of tubes which are so controlled being dependent upon the numberof impulses dialed. If ten impulses are dialed, all ten of the tube willionize in succession in response to successive impulses and will operatetheir anode relays.

In accordance with a further embodiment of the invention, the controlelectrodes of all ten tubes are connected in parallel to the secondarywinding of the transformer and anode potential is applied only to theanode of the first tub'e upon the initial closure of the dialing loop.The anode relay of each tube except the last, is provided with contactswhich, upon the operation of the relay, connect anode potential to theanode of:

the next succeeding tube.

The circuit functions in the following manner: Upon the initial closureofthe dialing loop, potential is connected to the anode of the firsttube through the winding-of the associated anode relay and an inductivesurge of potential is generated in the secondary winding of thetransformer which increases the negative bias on the control electrodesof all tubes. In response to the first dialing impulse, the dialing loopis momentarily opened thereby causing a surge of potential of theopposite polarity in the secondary winding of the transformer whichreduces the bias on the control electrodes of all the tubes to thebreakdown potential, but since the first tube is the only one which haspositive potential on its anode, only the first tube ionizes andoperates its anode relay over its cathode-anode ciscuit. This anoderelay closes a register operating circuit and connects positivepotential to the anode of the second or next succeeding tube. on thenextclosure of the dialing loop, the negative bias on the control electrodesof all tubes is increased but without eifect since the first tuberemains in its ionized condition and the second tube, al-

though supplied with anode potential, is blocked. On the next opening ofthe dialing loop, the resulting surge of potential in the secondarywinding of the transformer reduces the bias 'on the control electrodesof all tubes to the breakdown potential but since the first tube isalready ionized and the second tube only, of the remaining tubes, hasanode potential, only the second tube ionizes and operates its anoderelay. This anode relay closes a register operating circuit and connectspositive potential to the anode of the third or next succeeding tube. Ina similar manner, in response to successive closures and openings of thedialing ioop, successive tubes ionize and operate their anode relays,the number of tubes which are so controlled being dependent upon thenumber of impulses dialed.

A clearer understanding of the invention may be obtained from aconsideration of the following detailed description read in connectionwith Fig. 2 shows a subscribers loop and that portion of a sendercircuit involved in the recording of digits dialed by a subscriber. Inthis figure,

the control electrodes of all ten tubes are normally connected inparallel to the second winding of the transformer.

It is to be understood'that the invention is not limited to the circuitarrangementsshown in Figs. 5

1 and 2. as the number of tubes, anode relays and register relays may beincreased or decreased to perform the desired circuit functions.

Referring to Fig. 1, when a subscriber at substation I00- initiates acall. and is connected 1 through to the sender circuit in the usualmanner, the dialing loop is from ground through the winding of relayIII, through the contacts of the subscriber dial, over the subscribersloop, through the primary winding of transformer I02 to the negativeterminal of battery Ill, thereby energizing relay IOI. Relay IOI beingenergized, closes an obvious circuit for pulse change-over relay I 01which connects the positive terminal of battery not through the windingsoi anode relays I20 to I29, inclusive, to the anodes ofallten gaseousdischarge tubes IIOto II! inclusive, which are associated with anoderelays I20 to I20, respectively.

Pulse change-over relay I" is so constructed that it will remainenergized during all openings of the dialing loop except the last, foreach digit dialed. Uponthe final opening of the dialing loop for eachdigit, however, change-over relay I0! is deenergized.

The control electrode or grid of the gaseous discharge tube I'I0 isconnected to the negative terminal of battery I00 through the secondarywindthe filaments and the cathodes of tubes IIO to H0, inclusive.Negative potential is connected to 45 the cathodes of tubes H0 to 0,from the negative terminal of battery I06. The resistances I 50 to I50,inclusive, are inserted between the control electrodes of tubes III to0, respectively, and the negative terminal of battery I 04 in order tomaintain a slight negative potential on the control electrodes oftubesIII to 9. This potential is Just above the breakdown potential of .thetubes.

On the closure of the loop, an inductive 55 surge of potential isgenerated in the secondary winding of transformer I02 which increasesthe negative bias on the control electrode of tube I I0. It will beassumed that the subscriber dials the letter D as the first letter ofthe exchange code,

'which has the numerical equivalent of the digit 3. When the dialreturns to normal upon its release, 'it, in the usual manner, opens thedialing loop three times.

On the first opening of the dialing loop by the dial contacts, aninductive surge of potential of the opposite polarity is generated inthe secondary' winding of transformer I02 which reduces the bias on thecontrol electrode of tube m to such a degree that tube In immediatelyionizes and becomesconducting. with tube 0 in the conducting condition,anode relay I20 is energized in a circuit extendingfrom the negativeterminal of battery I06, cathodeand anode oi -tube no, winding of relaym, to negative grounded battery I03 through the front contact of relayI01. Relay I20,- being energized, closes its left front contact and itsright front contact. The closureof the left front contact of relay I20completes a pathfrom ground, through the front contact of relay I20, thewinding of register relay I30, to the negative terminal of battery I03,thereby causing the register relay I30 to become energized. Closure ofthe right front contact of relay I20 connects the control electrode oftube :II to the secondarywinding of transformer On the second closure ofthe dialing loop, an inductive surge of potential is generated in thesecondary winding of transformer I02 which increases the negative biason the grldsof tubes H0 and III. Tube IIO will remain in its ionizedcondition. Tube III will be blocked against ionization by the highnegative potential on its control electrode.

On the second opening of the dialing loop by the dial contacts, aninductive surge of potential is generated in the secondary winding oftransformer I02. This surge of potential opposes the negative bias onthe control electrode of tube III. Therefore, the negative bias on thecontrol electrode of tube III will be reduced to such a degree that tubeIII ionizes and becomes conducting. Withtube III in the conductingcondition, anode relay I2I is energized in a circuit extending from thenegative terminal of battery I06, cathode and anode of tube III, windingof relay I2I, to negative grounded battery I06,.

through the front contact of relay I0'I. Relay I2I, being energized,closes its left front contact and its right front contact. Closure ofthe left front contact of relay I20 completes a path from ground,through the front contact of relay I2 I the winding of register relayI3I' to the negative terminal of battery I03 thereby causing theregister relay I3I to become energized. Closure of the right frontcontact of relay I2l connects the control electrode of tube II2 to .thesecondary winding of transformer I02.

On the third closure of the dialing loop, an inductive surge ofpotential is generated in the secondary winding of transformer I02 whichincreases the negative bias on the control electrodes of tubes IIO, III,and H2. Tubes H0 and III will remain in their ionized condition. Tube II2 will be blocked against ionization by the high negative potential onits control electrode.

On the third and final opening of the dialing loop by the dial contacts,an inductive surge of potential is generated in the secondary winding oftransformer I02, which opposes the negative bias on the controlelectrode of tube H2. The

negative bias on the control electrode of tube II2 will be reduced tosuch a degree that tube II2 ionizes and becomes conducting. With tube H2in the conducting condition, anode relay I22 is energized in a circuitextending from the negative terminal of battery I06, cathode and anodeof tube II2, winding of relay I22, to negative grounded battery I06through the front contact of relay I0'I. Relay I22, being energized,closes its left front contact and its right front contact. Closure ofthe left front contact of relay I22 completes a path from ground,through the front contact of relay I22, the winding of register relayI32, to the negative terminal of battery I03, thereby causing theregister relay I32 to become energized. Closure of the right frontcontact of relay I22 connects the control electrode of tube II3 to thesecondary winding of transformer I02.

On this third and final opening of the dialing loop by the dialcontacts, relay IOI will become deenergized. in turn releasing relay.I0I' which opens its front contact thereby removing the negativegrounded battery from the anodes of 5 all tubes IIO to H9, inclusive.Tubes IIO, III and H2 will become deionized and non-conducting. Thiswillopen the holding circuits for anode relays I20, I2 I and I22,thereby permitting these relays to become deenergized and open their 10front contacts.- Opening of the right front contacts of relays I20, I2Iand I22 will remove the negative potential from the control electrodesof tubes III, H2, and 3. -Opening of the left front contacts of relaysI20, I2I, and I22 will 15 open the holding circuits for the registerrelays I30, I3 I, and I32, thereby permitting these register relays tobecome deenergized.

For succeeding digits dialed, relay IOI, relay I01, transformer I02 andtube IIO will function 20 in the manner describedhereinbefore. If thesucceeding digit dialed is 2 or a digit of higher value, tubes IIO toH9, inclusive, anode relays I20 to I29 inclusive, and register relaysI30 to I39 inclusive, will function in a manner similar 25 to thatdescribed hereinbefore for tubes III and H2, anode relays I2I and I22and register relays I3I and I32. The number of tubes, anode relays andregister relays operating in this case depends upon the number ofimpulses in the digit dialed. On the final opening of the dialing loopby the dial contacts,-relay IOI will become deenergized, in turnreleasing relay I01 which opens its right front contact thereby removingnegative grounded battery from the anodes of all tubes. The tubes becomenon-conducting and the associated relays release as described above.

Referring to Fig. 2, the control electrodes of all the tubes arenormally connected in parallel to the secondary winding of transformer202 and to the negative terminal of battery 204 which places a negativebias on the control electrodes of all tubes 2I0 to 2I9 inclusive. Thecondenser 205 is connected across the secondary winding of transformer202 in order to control the maximum voltage and the duration of thesurge of potential within proper limits for functioning tubes 2 I0 to2I9 inclusive. When a subscriber at substation 200 initiates a call andis connected through to the sender circuit in the usual manner, thedialing loop is established from positive grounded battery through thewinding of relay 20I, through the contacts of the subscriber dial, overthe subscribers line loop, through the primary winding of transformer202 to the nega tive terminal of battery 203, thereby energizing relay20I. Relay 20I being energized, closes a circuit for energizing relay260 from ground, through the front contact of relay 20I, through thewinding of relay 260 to the negative terminal 60 of battery 203. Relay260, being energized, locks up over a circuit closed from ground, theinner front contact of relay 260, conductor 250, the left back contactof relay 220, conductor 25I, resistance 26 I the winding of relay 260,to the negative terminal of battery 203. Closure of the outer frontcontact of relay 260 connects negative grounded battery over conductor252, the winding of anode relay 220, to the anode oftube 2I0, therebyplacing a positive potential on the anode of tube 2I0.

The filaments and the cathodes of all tubes 2 I0 to 2I9, inclusive, areheated by current from battery 203. This current is controlled byrheostats 240 to 249 inclusive, which are associated 75 with tubes 2|0to m, respectively. A negative potential is placed on the cathodes oftubes M to 2|! inclusive, from the negative terminal of battery 206.

On the closure of the dialing loop, an induc- 4 the dialing loop threetimes.

On the first opening of the dailing loop by the dial contacts, aninductive surge of potential of the opposite polarity is generated inthe secondary winding of transformer 202 which substantially reduces thebias on the control electrodes of tubes 2| 0 to" H9, inclusive. Tube 2l0immediately ionizes and becomes conducting. Tubes 2 to 2i9 inclusive,will not ionize because there is no positive potential on their anodes.With tube 210 in the conducting condition, anode relay 220 is energizedin a circuit extending from the negative terminal of battery 206,cathode and anode of tube 2l0, anode relay 220, conductor 252, the outerfront contact of relay 260, to negative grounded battery 206. Relay220,,being energized, closes its right front contact and its left outercontact and operates its left continuity contacts. Closure of the rightfront contact of relay 220 completes a path from negative groundedbattery through the outer front contact of relay 2B0, conductor 252, theright front contact of relay 220, anode relay 22! to the anode of 'tube2 Ii, thereby placing a positive potential on the anode of tube 2i i.Closure of the left outer front contact of relay 220 completes a pathfrom ground through the left outer front contact of relay 220, thewinding of register relay 230 to. the negative terminal of battery203,'thereby causing the register relay-230 to become energized. Closureof the left continuity contacts of relay 220 completes a path fromground, the inner front contact of relay 260, conductor 250, the leftinner front contact'of relay 220 to the side of relay 20i which isconnected to the dial, thereby short-circuiting the winding of relay20l. When the continuity contacts are fully operated, the previouslytraced locking circuit of relay 260 is opened.

Relay 20l will become deenergized and open its front contact therebyopening the operating circuit for relay' 260. Relay 260, however, willnot release immediately as it is held energized by the discharge ofcondenser 262 through the winding of relay 260, this condenser havingcharged through resistance 26l when the operating circuit of relay 260was established by the operation of relay 20l. The values of resistance28! and condenser 262 are such that relay 260 will remain energized fora definite time longer than the time elapsing between impulses of thedigit being dialed. Relay 260 will become deenergized a predeterminedtime after the final opening of the dialing loop after each digit isdialed.

On the second closure of the dialing loop, an

- inductive surge. of potentialis generated in the secondary winding oftransformer 202 which increases the negative bias on the grids of tubes2m to H9. Tube 2l0 will remain in its ionized condition. Tube 2 will beblocked against ionization by the high negative potential on its controlelectrode. Tubes M2 to 2| 9 will not ionize since there is no positivepotential on their associated anodes.

On the second opening of the dialing loop by the dial contacts,aninductive surge of potential is generated in the secondary winding oftransformer 202. This surge of potential opposes the negative bias onthe control electrode of tube 2| I. Therefore, the negative bias on thecontrol electrode of tube 2 will be reduced to such a degree that tube 2ionizes and becomes conducting. With tube 2 in the conducting condition,anoderelay 22l is energized in a circuit ex-. tending from the negativeterminal of battery 206, cathode and anode of tube 2, winding of anoderelay 22!, right contact of relay 220, conductor 252, the outer frontcontact of relay 260, to negative grounded battery. Relay 22l, be.- ingenergized, closes its. right front contact and its left outer contactand operates its left continuity contacts. Closure of the right frontcontact of relay-220 completes a path from negative grounded battery,the outer front contact of relay 260, conductor 252, the right frontcontact of relay 22l', winding of anode relay 222 to the anode of tube2| 2, thereby supplying a positive potential to the anode of tube 2l2.Closure of the left outer front contact of relay 22I completes'a pathfrom ground, the winding of register relay 23l, to the negative terminalof battery 203, thereby causing the register relay 2: to becomeenergized. Closure of the left continuity contacts of relay 22icompletes a path from ground, the inner front contact of relay 260,conductor 250, the left continuity contacts 9 of relay 22l, conductor25l, resistance 26l, winding' of relay 260 and in parallel throughcondenser 262 to the negativeterminalof battery 203, thus holding relay260 operated and again charging condenser 262. When, however, thecontinuity contacts of relay 22l become fully operated, the normallyclosed contacts open,

opening the previously traced locking circuit for relay 260. However,the condenser 262 which is shunted across relay 260 and resistance 26lnow discharged through relay 200 and the resistance 26l and causes relay260 to remain energized for-a definite period of time after the impulseas hereinbefore described for the first impulse.

On the third closure of the dialing loop, an inductive surge ofpotential is generated in the secondary winding of transformer 202 whichincreases the negative bias on the control electrodes of tubes2l0 to2l9. Tubes2l0and2ll will remain in their ionized condition. Tube 2l2will be blocked against ionization by the high negative potential on itscontrol electrode. Tubes 2l3 to 219 will not ionize since there is nopositive potential on their associated anodes.

On the third and final opening of the dial ing loop by the dialcontacts, an inductive surge of potential is generated in the secondarywinding of transformer 202. This surge of potential opposes the negativebias on the control electrode of tube 2| 2. Therefore, the negative biason the control electrode of tube 2|2 will be reduced to such a degreethat tube 2l2.ionizes and becomes conducting. With tube 2 I 2 in theconducting condition, anode relay 222 is energized in a circuitextending from the negative terminal of battery 206, cathode and anodeof tube 2l2, anode relay 222, right contact of' relay 22l, conductor252, the outer front contact of relay 260 to negative grounded battery.Relay 222, being energized, closes its right front contact and its leftouter contact and operates its left continuity contacts. Closure of theright front contact of relay 222 completes a path from negative groundedbattery through the outer front-contact of relay 260, conductor 252, theright front contact of relay 222, winding of anode relay 223 to theanode of tube 2 !3, thereby placing a positive potential on the anode oftube 2 3. Closure of the left outer front contact of relay 222 completesa path from ground, through the winding of register relay 232, to thenegative terminal of. battery 203, thereby causing the register relay232 to.become.energized. Closure of the left continuity contacts ofrelay 222 completes a path from ground, the inner front contact of relay260, conductor 25!], the left inner front contact of relay 22!, the leftcontinuity contacts of relay 222, conductor 25!, resistance 26!, windingof relay 260 and in parallel through condenser 262 to the negativeterminal of battery 203, holding relay 263 operated and again chargingcondenser 262. When, however, the continuity contacts of relay 222become fully operated, the normally closed contacts open the lockingcircuit for relay 260. However, condenser 262 which is shunted acrossrelay 260 and resistance 26! now discharges through relay 26B andresistance 26! and causes relay 260 to remain energized for a definiteperiod of time after the impulse as described hereinbefore for the firstand the second impulses.

On this third andfinal opening of the dialing loop by the dial contacts,relay 250 will become .deenergized and will open its left outer frontcontact, thereby removing the negative grounded battery from the anodesof tubes 2H], 2!!, 2!2 and 2!3, inclusive. Tubes H0, 2!!, and 2l2 willbecome deionized and non-conducting. This will open the holding circuitsfor anode relays 220, 22!, and 222, thereby permitting these relays tobecome deenergized and open their front contacts and close their backcontacts. Opening of the rightfront contacts of relays 220, 22! and 222will open the individual anode circuits to the anodes of tubes 2, 2!2,2l3. Opening of the left outer front contacts of relays 220, 22!, and222 will open the holding circuits for the-register relays 230, 23! and232, thereby permitting these register relays to become deenergized.Opening of the left inner front contacts of relays 220, 22!, and 222will open the circuit used for short-circuit relay 2!!! and the circuitfor charging condenser 262 during pulsing. Closure of the left backcontact of relay 220 restores the locking circuit for relay 260 so thatit will again lock up on closure of the dialing loop when the next digitis dialed.

What is claimed is:

1. In a signaling system, an impulsing device, an impulse .responsivedevice, a. control circuit extending between said devices, a group ofgaseous conductor tubes at said responsive device, a

relay in the cathode-anode circuit of each of said tubes operable uponthe ionization of the tube with which it is associated, means fornormally rendering the first of said group of tubes operable in responseto the first impulse over said control circuit, and means controlledupon the operation of each of said relays for preparing the nextsucceeding tube of said group for operation whereby in response tosuccessive impulses said tubes successively ionize and operate theirassociated anode relays.

2. In a signaling system, an impulsing device, an impulse responsivedevice, a. control circuit extending between said devices, a group ofgaseous conductor tubes at said responsive device, a" relay in thecathode-anode circuit of each of said tubes operable upon theionizationof the tube with which it is associated, a transformer for connectingsaid control circuit with the control electrodes of said tubes havingits windings so poled that the control electrodes of said tubes arebrought to the ionization potential only on the opening of said controlcircuit by said impulsing device, said first tube being operable inresponse to the first opening of said control circuit, and meanscontrolled by the operation of each of said relays for preparing thenext succeeding tube for operation whereby in response to successiveopenings of said control circuit said tubes successively ionize andoperate their associated anode relays.

3. In a signaling system, an impulsing device, an impulse responsivedevice, a control circuit extending between said devices, a group ofgaseous conductor tubes at said responsive device, a

. relay in the cathode-anode circuit of each of said tubes operable uponthe ionization of the tube with which it is associated, means fornormally connecting the control electrode of the first of said group oftubes with said control circuit, and means controlled upon the operationof each of said relays for connect ng the control electrode of the nextsucceeding tube with said control circuit whereby in response to aseries of impulses ionization potential is successively applied 45 tothe control electrodes of said tubes and said tubes successively ionizeand operate their associated anode relays.

4. In a signaling system, an impulsing device,

an impulse responsive device, a control circuit W extending between saiddevices, a group of, gaseous conductor tubes at said responsive device,a relay in the cathode-anode circuit of each tube operable upon theionization of the tube with which it is associated, means for normallyconnecting the control electrodes of said tubes with said controlcircuit, and means controlled upon the operation of each of said relaysfor connecting anode potential to the anode of the next succeeding tubewhereby in response to a series of impulses over said control circuitsaid tubes ionize in succession and operate their associated anoderelays.

PHILIP HUSTA.

